/*
 * Copyright 2007 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package fr.upstlse.glre.client.vitrine;

import com.google.gwt.user.client.ui.AbstractImagePrototype;
import com.google.gwt.user.client.ui.Composite;
import com.google.gwt.user.client.ui.ImageBundle;
import com.google.gwt.user.client.ui.TreeImages;

/**
 * A 'sink' is a single panel of the kitchen sink. They are meant to be lazily
 * instantiated so that the application doesn't pay for all of them on startup.
 */
public abstract class Page extends Composite {

	/**
	 * An image provider to make available images to Sinks.
	 */
	public interface Images extends ImageBundle, TreeImages {
		AbstractImagePrototype gwtLogo();
	}
	
	/**
	 * Encapsulated information about a sink. Each sink is expected to have a
	 * static <code>init()</code> method that will be called by the kitchen sink
	 * on startup.
	 */
	public abstract static class SinkInfo {
		private Page instance;
		private String name, description;

		public SinkInfo(String name, String desc) {
			this.name = name;
			description = desc;
		}

		public abstract Page createInstance();

		public String getColor() {
			return "#2a8ebf";
		}

		public String getDescription() {
			return description;
		}

		public final Page getInstance() {
			if (instance != null) {
				return instance;
			}
			return (instance = createInstance());
		}

		public String getName() {
			return name;
		}
	}

	/**
	 * Called just before this sink is hidden.
	 */
	public void onHide() {
	}

	/**
	 * Called just after this sink is shown.
	 */
	public void onShow() {
	}
}
